What are the common sensor failures and their solutions for brushless motor motor automatic load tester?
The common sensor failures of brushless motor motor automatic load tester and their solutions are as follows:
1、Rotational speed sensor failure
l Failure phenomenon
Abnormal display of rotational speed: the motor rotational speed displayed by the tester does not match with the actual rotational speed, and the rotational speed value may jump, display zero or obviously deviate too much.
Abnormal motor control: Due to inaccurate feedback of rotational speed, the motor cannot run according to the set speed during testing, and there are problems such as unstable speed, jittering or inability to reach the target rotational speed.
l Failure causes
Sensor installation problems: inaccurate installation position, resulting in too large or too small a gap between the sensor and the motor shaft, affecting the signal acquisition; loose installation, so that the sensor displacement in the operation process, the signal is interfered with.
Sensor damage: after long-term use, the sensor's internal electronic components may be aging, damage, such as Hall component failure, magnet demagnetization, etc.; by external electromagnetic interference, vibration or shock, resulting in sensor damage.
Signal transmission problem: the cable connecting the sensor and the control system of the tester is broken, short-circuited or poorly contacted, so that the rotational speed signal can not be transmitted to the control system normally.
l Solution
Check the installation: Re-adjust the installation position of the sensor to ensure that the clearance between it and the motor shaft meets the requirements, and tighten the mounting bolts to prevent loosening.
Replacement of the sensor: use professional tools and equipment to detect the sensor, if the sensor is found to be damaged, replace the sensor with the same type and specification in time.
Exhaust line: check whether the signal transmission cable is broken, fractured or poor contact, if necessary, replace the cable or repair the connection point.
2、Torque sensor failure
l Fault phenomenon
Inaccurate torque measurement: the torque value obtained from the test deviates greatly from the actual torque, which may lead to misjudgment of the motor torque performance.
Unstable torque signal: The torque display value fluctuates greatly, failing to provide stable measurement data and affecting the accuracy and reliability of the test results.
l Failure causes
Sensor accuracy problem: the torque sensor itself is not accurate enough, or the accuracy decreases after a long time of use, so it cannot measure the torque accurately.
Overload damage: During the test, the torque output of the motor exceeds the rated measurement range of the torque sensor, resulting in damage to the strain gauges or other components inside the sensor.
Zero drift: Due to environmental temperature changes, power supply voltage fluctuations and other factors, the zero point of the torque sensor drifts, affecting the measurement accuracy.
l Solution
Calibrate the sensor: Use high-precision torque calibration equipment to calibrate the sensor and adjust its measurement accuracy to ensure the accuracy of the measurement data.
Replace the sensor: If the sensor is damaged due to overload, etc., it should be replaced with a new torque sensor in time, and choose a product with appropriate range and accuracy according to the testing requirements.
Compensation of zero drift: increase the temperature compensation circuit in the test system or use software algorithms to compensate for zero drift, reduce the impact of environmental factors on the measurement results.
3、Temperature sensor failure
l Failure phenomenon
Temperature display error: the motor temperature displayed by the tester does not match the actual temperature, and the temperature value may be too high or too low error display.
Mis-action of overheating protection: Due to inaccurate measurement of the temperature sensor, the tester triggers the overheating protection when the motor is not really overheated, which interrupts the test; or when the motor is actually overheated, the overheating protection fails to take action in time, which is a hidden danger.
l Failure causes
Aging of the sensor: the temperature sensor works in a high temperature environment for a long time, its performance will gradually aging, resulting in a decline in measurement accuracy.
Poor contact: the contact between the temperature sensor and the motor surface is not tight, there is an air gap, affecting the heat transfer, resulting in inaccurate measurement of temperature.
Electromagnetic interference: Strong electromagnetic fields in the test environment may interfere with the signal of the temperature sensor, causing deviations in the measurement results.
l Solution
Replacement of sensors: Check the performance of temperature sensors regularly, if aging is found, replace the temperature sensors with new ones in time.
Improve contact: Clean the contact parts of the motor surface and temperature sensor, use thermally conductive silicone grease and other materials to fill the gap to ensure good heat conduction; at the same time, check whether the sensor is firmly installed and fixed to avoid loosening.
Shielding interference: the temperature sensor signal cable using shielding measures, such as the use of shielded wires, and will be shielded reliably grounded to reduce the impact of electromagnetic interference on the signal.
4, current sensor failure
l Fault phenomenon
Current measurement deviation: the measured motor operating current does not match the actual current, which may lead to misjudgment of the motor power consumption, load state and so on.
Abnormal overcurrent protection: The current sensor failure may make the overcurrent protection device unable to detect the overcurrent of the motor in time, or trigger the overcurrent protection mistakenly under normal current conditions.
l Failure causes
Sensor damage: The electronic components inside the current sensor, such as the transformer, amplifier, etc., may be damaged due to overheating, overvoltage and other reasons, resulting in inaccurate measurement.
Magnetic field interference: the surrounding strong magnetic field will affect the measurement accuracy of the current sensor, especially the Hall effect current sensor, which is more sensitive to magnetic fields.
Improper selection of range: If the selected current sensor range is too large or too small, it may lead to a decrease in measurement accuracy, and the actual current of the motor cannot be measured accurately.
l Solution
Repair or replacement: Repair the damaged current sensor or directly replace it with a new one to ensure its normal operation.
Shield the magnetic field: take magnetic shielding measures for the current sensor, such as using magnetic shielding cover, etc., to reduce the interference of the external magnetic field.
Correct selection: According to the rated current of the motor and test requirements, select the appropriate range and accuracy of the current sensor to ensure the accuracy of the measurement.
※ If you still can't solve the problem by the above ways and means, please contact the technical specialist of Xinhui Mechanical & Electrical Equipment Co.
